Heretofore, there have been many sealed batteries known for comprising a power generation element which includes positive and negative electrode plates and is housed in a battery case. For example, a few examples thereof are disclosed in Patent Documents 1 and 2.
In a battery of Patent Document 1, a negative electrode and a positive electrode are connected to current collector plates respectively. Each current collector plate is provided with a connecting projection which is fitted in a connecting hole perforated in a side wall of a battery case. Ends of the connecting projections of adjoining cells are welded to each other to connect the cells in series (see FIGS. 2 and 7 and a relevant explanation thereto in Patent Document 1).
In a battery of Patent Document 2, a negative electrode and a positive electrode are connected to current collector plates respectively. A connecting hole is perforated in a side wall of a battery case. A fitting is inserted in the connecting hole. The current collector plates of the adjoining cells are welded to each other through the fitting, connecting the cells in series (see FIGS. 2 and 8 and a relevant explanation thereto in Patent Document 2).